Fabric softening

ABSTRACT

A HIGH CONCENTRATION FABRIC SOFTENING EMULSION IS OBTAINED BY COMBINING A QUATERNARY AMMONIUM FABRIC SOFTENTER AND AN AMIDOIMIDAZOLINIUM SULFATE FABRIC SOFTENER, THE LATTER BEING DERIVED FROM C14-C18 FATTY ACIDS CONTAINING AT LEAST 80% SATURATED C16 AND C18 ACIDS. LOW TEMPERATURE STABILITY IS PROVIDED BY THE ADDITIONAL PRESENCE OF AN AMIDOIMIDAZOLINIUM SULFATE DERIVED FROM C14-C18 FATTY ACIDS CONTAINING AT LEAST ABOUT 10% OLEIC ACID.

United States Patent 3,681,241 FABRIC SOFTENING Jerome Rudy, Livingston, N.J., assignor to Lever Brothers Company, New York, N.Y. No Drawing. Filed Mar. 4, 1968, Ser. No. 709,879 Int. Cl. Clld 3/26; D06m 13/46 US. Cl. 2528.75 4 Claims ABSTRACT OF THE DISCLOSURE A high concentration fabric softening emulsion is obtained by combining a quaternary ammonium fabric softener and an amidoimidazolinium sulfate fabric softener, the latter being derived from C -C fatty acids containing at least 80% saturated C and C acids. Low temperature stability is provided by the additional presence of an amidoimidazolinium sulfate derived from 0 -0 fatty acids containing at least about oleic acid.

The present invention relates to the art of fabric softening formulations. More specifically, the present invention relates to a fabric softening formulation containing a high concentration of active ingredients.

In the fabric softening art, it is well known to prepare fabric softening formulations which are adapted for use in the rinse cycle of conventional home-laundry washing machines. As a general rule, any one of a wide variety of softening agents may be used, and they are normally formulated as dispersions in water containing from about 4% to about 7% of the active ingredients.

It has been recognized for some time that it would be desirable as a matter of convenience to employ the fabric softening formulation concurrently with the detergent in the wash cycle of the washing machine. In many of the home laundry washing machines now in use, the machine is so designed that in order to use a rinse cycle fabric softener it is necessary for the housewife to watch the cycle carefully, and to interrupt the cycle just before the final washing step to add the fabric softening agent, because no special provision has been made for dispensing fabric softeners at the time of the final rinse. The use of fabric softeners in such machines manifestly would be made considerably more convenient if it were possible for the housewife to add the fabric softener together with the laundry detergent, whereby the softener would act concurrently with the detergent simultaneously to wash and to soften the fabrics.

Conventional fabric softening formulations can be used as wash-cycle softeners. However, in order to obtain a reasonable amount of softening it is necessary to use generally in the order of twice the normal amount of formulation. Because this would require the housewife to maintain large quantities of fabric softening formulations on her shelves, and would involve an apparently wasteful use of fabric softeners, housewi'ves are reluctant to employ the fabric softening formulations currently available as washcycle softeners.

To overcome this difficulty, it would be desirable to prepare a high potency fabric softening formulation which, when used in a conventional quantity, would provide effective fabric softening in the presence of detergents in the wash-cycle of the home-laundry machine. For this purpose, a fabric softening formulation containing in the order of 10%-12% active ingredients would be needed. It has not been possible heretofore to prepare emulsions of such a high concentration employing the commercially accepted fabric softeners available. The generally elfective fabric softeners which have found widespread commercial acceptance, such as the di-(higher alkyl)-di- (lower alkyl) ammonium salts, cannot be prepared into emulsions which 3,681,241 Patented Aug. 1, 1972 "ice are stable in high concentrations. Using the typical commercially available fabric softening agents, formulations containing a maximum of 7% to 81% active can be prepared without incurring stability difiiculties.

In accordance with the present invention, a novel mixture of fabric softening components has been discovered which may be formulated in aqueous emulsions containing about 8.0% to 13% active ingredients.

The combination of fabric softening ingredients of the present invention consists essentially of:

(A) From 3.5 to 6.5 parts (by weight) of a quaternary ammonium compound having the formula:

(B) From 3.5 to 6.5 parts (by weight) of an alkyl amido imidazolinium alkylsulfate having the formula:

(C) From 0 to 3 parts (by weight) of a fatty amido imidazolinium alkylsulfate having the formula:

In the foregoing formulas, R and R are each an aliphatic acyclic hydrocarbon radical having 16 to 20 carbon atoms, R is a lower alkyl radical having from 1 to 3 carbon atoms, R; is a lower alkyl radical having from 1 to 3 carbon atoms, R is methyl or ethyl, R is the residue derived from C -C fatty acids said acids having at least C and C acids, and no more than 6% unsaturated C fatty acids, and R is the residue of C to C fatty acids having from 10% to octadecenoic acid, not more than about 40% octadecanoic acid, and not more than about 35% tetradecenoic acid.

Representative compounds which may be used include:

distearyl dimethyl ammonium chloride ditallow dimethyl ammonium chloride dihexadecyl dimethyl ammonium bromide distearyl di(isopropyl) ammonium methosulfate the amidoethyl imidazolinium ethylsulfate derived from hardened tallow fatty acid the amido ethyl imidazolinium ethylsulfate derived from hydrogenated oleic acid 1-methyl-1-stearylamidoethyl-Z-heptadecyl imidazolinium methosulfate l-methyl-l-oleylamido ethyI-Z-heptadecyl imidazolinium methosulfate the amidoethyl imidazolinium ethosulfate derived from unhardened tallow fatty acids.

The combination of fabric softening active ingredients of the present invention may be employed to prepare fabric softening formulations in accordance with technology well known to those skilled in the art. Thus an aqueous dispersion of the mixed fabric softening active agents is prepared in a concentration in the order of 9% to 12%. Additional agents may be employed for improving various other properties thereof, which agents may include, but are not limited to, moderate molecular weight quaternary ammonium salts (e.g., dicocodimethyl ammonium chloride) for improving the freeze-thaw stability of the formulation, as well as other supplementary low temperature stabilizers, optical brighteners, colorants, electrolytes (which are effective as viscosity regulators), and the like.

In understanding the present invention it should be recognized that emulsion stability in fabric softening formulations refers to three separate factors, namely, the stability of the emulsion at room temperature (approximately 80 F.), the stability of the emulsion under freezing conditions (about F.), and the stability of the emulsion with respect to cyclical freezing and thawing conditions. A deficiency in any one of these factors may make the product unsatisfactory depending on the conditions which the product may be subjected to during transit and marketing. The binary mixture of fabric softening active ingredients of classes (A) and (B) above, according to the present invention has acceptable room temperature stability in highly concentrated emulsions. This is in contrast to the stability of the ingredients when taken separately.

The distearyldimethyl ammonium chloride and the amidoimidazolinium salts of class (B), however, when separately tested for low temperature stability in a mixture wherein both components are present at a total of concentration, yield emulsions which irreversibly gel when subjected to temperatures at 0 F. The imidazolinium alkyl sulfates of class (C) above have been found to exhibit acceptable stability in high concentrations at both the 0 F. and at room temperature; however, this class of compound has been found to be substantially less effective as a fabric softener in the presence of detergents than either of the imidazolinium alkyl sulfates of class (B) above, or the distearyl dimethyl ammonium salts. Surprisingly, it has been found that the combination of fabric softening ingredients in accordance with the present invention is both highly effective in the presence of detergents, and, additionally, can be prepared in high potency emulsions which are stable both at room temperature and at 0 F. If the final formulation is not liable to be exposed to cold temperatures, component (C) may be omitted. However, for shipment through normal commercial channels in the cooler areas, the presence of at least about 1% of component (C) is desirable.

As already indicated, a third aspect of emulsion stability which may be important is stability against cyclical freezing and thawing conditions. To provide this additional stability (as well as to provide further low temperature stability), additional stabilizers may be present. Moderate molecular weight quaternary ammonium compounds and certain nonionic and amphoteric compounds have been found to be eifective as low temperature stabilizers which provide freeze-thaw stability. Accordingly, in the preferred embodiments of the present invention, the novel mixture of fabric softening active ingredients described above will be employed together with these further stabilizing agents.

Still another desirable attribute of a fabric softening emulsion is that the emulsion should preferably have a viscosity in the order of 200 to 500 cp. for optimum consumer acceptance. In order to control the viscosity of the fabric softening formulation it will normally be desired to regulate the amount of ionizable salts present as will be hereinafter discussed. Homogenization of the finished fabric softening emulsions will also usually be required. As is well known to those skilled in the art, homogenizers conventionally are adapted to subject the liquids being homogenized to extreme shearing action by forcing that liquid through an appropriately regulated orifice. The effective amount of homogenization which may be obtained is commonly measured in commercial homogenizing operations by observing the pressure and temperature of the material subjected to the homogenization. In the case of compositions prepared in accordance with the present invention, homogenization pressures about 1500 to about 2300 pounds per square inch and homogenization temperatures in the order of to F. are preferred.

It will be apparent in the foregoing discussion that the fabric softening formulation of the present invention will consist essentially of a number of ingredients in combination. Typical formulations within the preferred concept of the present invention will consist essentially of the following ingredients:

The mixture of fabric softening ingredients has already been described above. The remaining ingredients in the foregoing formulation may be more specifically described as follows:

The moderate molecular weight quaternary ammonium compounds which are used to improve the emulsion stability at low temperatures, generally have from 1 to 3 acyclic aliphatic hydrocarbon radicals containing from about 10 to about 14 carbon atoms, and from 1 to 3 lower alkyl radicals containing from about 1 to about 3 carbon atoms. The aliphatic hydrocarbon radicals may be straight or branched chain, and may be saturated or unsaturated. For commercial convenience, these radicals are usually derived from natural sources such as coconut oil, although synthetic sources may be used. Lower alkyl radicals may be straight or branched chain such as methyl, ethyl, propyl or isopropyl. The anion portion of the quaternary ammonium compound may :be sulfates, halides, or alkyl sulfates, especially chloride, bromide, iodide, sulfate, methosulfates and ethyl sulfate ions.

Preferred compounds have two aliphatic radicals and two lower alkyl radicals. Illustrative compounds are didecyl diethyl ammonium chloride, and ditetradecyl dimethyl ammonium chloride. A preferred compound is dicocodimethyl ammonium chloride. Monoand the trisubstitute quaternary compounds may also be used such as monococotriethyl ammonium bromide and tricoco monomethyl ammonium methosulfate. Such compounds have greater or lesser value as emulsion stabilizers depending on the number of aliphatic groups on the ammonium nitrogen. Accordingly, greater or lesser amounts of these comupounds may be used.

While an optional ingredient, the foregoing moderate molecularly weight quaternary ammonium compounds, when present, normally consititute from 1% to 2% of the formulation for best results.

Additionally, it may be desired to provide for nonionic or amphoteric supplemental low temperature stabilizers up to about 1% to 2%. Such supplemental stabilizers are normally desired when the emulsions would otherwise require the presence of excessive amounts of the moderate molecular weight cationic stabilizers, i.e., in excess of about 2%. Under these circumstances up to about 1% to 2% of a material selected from the group consisting of N-lauryl amino propionic acid, dimethyl coco amine oxide polyoxylene ethylene ester of tall oil having from 8 to 30 ethylene oxide units, polyoxyethylene sorbitan monostearate having from 6 to 20 ethylene oxide units, dodecyl methyl sulfoxide, ethylene oxide condensates of straight and branched chain unsubstituted aliphatic alcohols having from 8 to 20 carbon atoms and having from 1 to 30 ethylene oxide units, and the alkylphenolethylene oxide condensate having from 8 to 12 carbon atoms in the alkyl chain and from 8 to 30 ethylene oxide units. Amounts greater than about 1% of the foregoing supplementary stabilizers are generally not preferred because large amounts thereof adversely affect the fabric softening ability of the fabric conditioning active ingredients which are present. Hereinafter, and in the appended claims, the compounds of this class Will be termed supplemental emulsion stabilizers.

The foregoing stabilizers also act as dispersing agents, that is, they prevent the formation of objectionably large particles of the cation-anion complex formed when the composition of the present invention is employed in combination with anionic detergents. This prevents the heterogeneous absorption of the complex by the cloth.

In addition to providing for the presence of the stabilizer in the emulsion of the fabric softening compound, certain other conditions should be observed in order to assure satisfactory properties. Among these desirable properties is a viscosity which is regulated to provide optimum consumer appeal. Typically, a viscosity in the order of 200-500 centipose is desired.

In order adequately to control the viscosity of the fabric softening emulsions, the amount of ionizable salts present should be between about 0.005% and 0.1%, and further, the amount of lower aliphatic alcohols present should be less than 1.0%. At extremely low concentrations of ionizable salt, i.e., less than about 0.005%, decreasing the amount of ionizable salt increases the viscosity of the emulsion. On the other hand, when the salt concentration is in excess of about 0.1%, increasing the amount of ionizable salt also tends to thicken or to solidify the emulsion.

Typical ionizable salts affecting the fluidity are the salts of the mineral acids with bases such as the ammonium and alkali metal salts, i.e., salts of sodium, potassium and ammonium with the halides (such as chlorides, bromides and iodides), nitrates, phosphates, sulfates, and other such salts resulting as by-products in the manufacture of the various raw materials used in preparing fabric conditioning emulsions. If hard water is used in the preparation of the fabric conditioning emulsion, the ionizable salts therein also have been observed to affect the viscosity of the emulsion. Such salts include iron chloride, aluminum chloride and the alkaline earth chlorides such as calcium chloride, barium chloride, as well as the ionizable nitrates, sulfates, and phosphates of the aforementioned metals. Other ionizable salts affecting the fluidity of the emulsion are soluble salts of the above-mentioned metallic ions with organic acids containing from 1 to 4 carbon acids. These include the aliphatic acids such as formic acid, acetic acid, propionic acid, and the substituted acids such as hydroxy aliphatic acids, i.e., citric acid, tartaric acid, malonic acid and maleic acid.

In the preferred practice of this invention, the fabric conditioning formulations are prepared from ingredients selected so that they will substantially be free of salts. To the resulting substantially salt-free emulsion a controlled amount of an ionizable salt is added to regulate the viscosity thereof. Salts of the hydroxy aliphatic acids such as sodium citrate, are particularly desirable for their purpose.

Further, as mentioned, the amount of lower aliphatic alcohols should not exceed about 1%. While in the normal case one would expect that alcohols such as methyl alcohol, ethyl alcohol or isopropyl alcohol would improve the low temperature stability of aqueous emulsions, it has been discovered that in the presence of emulsions of fabric softening ingredients, excessive amounts of such alcohols adversely affecting the low temperature stability. In the preferred formulations the emulsion is substantially free of alcohol. Many of the commercially available raw materials used in formulating fabric softening emulsions contain small amounts of alcohol, however; and therefore it is not practical in many instances to prepare alcohol-free emulsions. Satisfactory results are generally obtained if the amount of alcohol is below about 1%.

In addition to the foregoing ingredients which have been discussed in detail, it will be apparent to those skilled in the art that the variety of other ingredients may be present which do not affect the essential nature of the fabric softening formulation. Indeed, many such ingredients may be provided for the purpose of improving other properties thereof or for the purpose of improving consumer acceptance. Typical ingredients include, but are not limited to, optical brighteners, colorants, perfumes, and the like.

For a further understanding of the present invention, reference may be had to the following examples;

A wash-cycle fabric softening formulation was prepared having the following composition:

Ingredients: Percent active Distearyldimethyl ammonium chloride 4 The amido-ethyl-imidazoline ethyl sulfate de- Water, balance to make 1 Alrfonic 1418-6 is the ethylene oxide condensate of mixed alcohol containing about 14 to 18 carbon atoms. the alcohols having been prepared by a Ziegler polymerization. The condensate contains 9 ethylene oxide units for each mole of al- 001101.

The foregoing was prepared with ingredients which were substantially free of salts and alcohols.

The above-described formulation was evaluated for fabric softening in the presence of a typical commercial nonionic-based, built detergent A and in the presence of a typical commercial alkyl benzene sulfonate-based, built detergent B, in each case with and without the presence of bleach. A test panel subjectively evaluated the washed cloths for softness. The lowest score indicates the best softening. For purposes of comparison, a series of samples were included in which no softener was present. The following results were obtained:

Terry Diapers 2 oz. 2 oz.

test 2% oz. No test 2% oz. No softtest softsofttest softener softener ener ener softener cner A without bleach:

.5 11 21. 5 21. 5 9 .5 18 14 22 21 9 17 11 Wash 17 9 24 A" bleach 1st wash 18 12 24 ll 17 21 2nd wash 17 16 21 10 21. 5 l8. 5 4th wash 18 ll 24 B without bleach:

1st wash l2 13 22 19 14. 5 21. 5 2nd Wash 21 12 21 17 13 23 4th Wash 15 18 21 B bleach:

1st wash 9 9 24 15 15 20 2nd wash 20 12 17 14 16 18 4th wash. 18 10 23 It was noted during the course of the foregoing tests, that detergency was not affected by the presence of the fabric softener. The presence of the fabric softener did, however, affect the sudsing of the detergent. When used in combination with B, the suds levels was depressed while when used in combination with A the suds level was increased somewhat. When used in combination with A, however, the cloth yellowing which is typically encountered when cationic fabric softeners are used in combination with nonionic detergents was noted.

7 EXAMPLE 2 The fabric softening formulation described in Example 1 was subjected to homogenization to improve the viscosity thereof. Prior to homogenization the emulsion had a viscosity of approximately 1100 centipoises. When subjected to homogenization at various homogenizing pressures, the following results were obtained:

Homogenizing pressure Viscosity (pounds per square inch): (centipoises) EXAMPLE 3 The physical stability of the emulsion described in Example 1 was examined. The emulsion was a stable, pourable fluid at room temperature (80 F.) and at F. The emulsion was, moreover, subjected to freezing (0 F.) and thawing (80 F.) conditions on a 24 hour cycle for seven times (a total of one week). It was found that the cyclic freezing and the thawing did not affect the emulsion stability.

Further formulations which are illustrative of the present invention are set forth in the following table:

Quaternary D 4. 5 6 Quaternary E 6. 5 Imidazollne F 2 2 Imadazoline H- Imadazollne I Quaternary T1 2 Quaternary M. 2 Quaternary N 2 Na-N-lauryl aminopropionate Di-hydroxyethyl-coco amine oxide 1 Dodecyl methyl sulf i 2 NHiC 0.005 'R'Rr 0.1 0.05

Potassium tarh' Ethyl nlnnhnl Water Norm- D=Diarachydyl dimethyl ammonium chloride. E=Di Tallow" dimethyl ammonium sulfate. F=1-methyl-1-alkyl amidoethyl-Z-alkyl imidazolinium methyl sulfate, where the alkyl group is derived fromtallow fatty acid. G=l-methyl-l-alkylarnidoethyl-Z-alkyl imldazolinium methyl sulfate, where the alkyl is derived from oleic acid hydrogenated to an I.V. of 40450. H=l-etllixylgl-steary1amidoethyl-2-heptadecyl imidazolinium ethyl s ae. I=l-elgfiyl-l-pahnitylamidoethyl-2-pentadecyl imidazolinium ethyl (b) from 3.5 to 6.5 parts (by weight) of an alkyl amido imidazolinium alkylsulfate having the for- 1 Balance to make 100% (c) up to 3 parts (by weight) of a fatty amido imidazolinium alkylsulfate having the formula:

NOH2 Q R1-C/ o N Ihii-NlI-Cii Rs there being a total of from 8.5% to 13% by weight of said softeners (a), (b) and (c) in said formulation and there being at least 1% by weight of softener (c) and in the foregoing formulas, R and R are each aliphatic acyclic hydrocarbon radicals having 16 to 20 carbon atoms, R is a lower alkyl radical having from 1 to 3 carbon atoms, R, is a lower alkyl radical having from 1 to 3 carbon atoms, R is methyl or ethyl, R is the hydrocarbon residue of C -C fatty acids said acids having at least C and C acids, and not more than 6% unsaturated C fatty acids, and R is the hydrocarbon residue of (E -C fatty acids having from 10% to octadecenoic acid, not more than about 40% octadecanoic acid, and not more than about 35% tetradecenoic acid;

(d) up to 2% by weight of a supplementary low temperature stabilizer having the formula wherein R is an aliphatic hydrocarbon radical containing from about 10 to about 14 carbon atoms, R, and R are each selected from the group consisting of aliphatic hydrocarbon radicals having from 10 to 14 carbon atoms and lower alkyl radicals having from 1 to 3 carbon atoms and R is a lower alkyl radical having from 1 to 4 carbon atoms, and A is a water solubilizing anion;

(e) up to about 2% by weight of a supplementary emulsion stabilizer selected from the group consisting of N-lauryl-amino propionic acid dimethyl coco amine oxide, the polyoxyethylene ester of tall oil having from 8 to 30 ethylene oxide units, polyoxyethylene sorbitan monostearate containing from 6 to 20 ethylene oxide units, dodecyl methyl sulfoxide, ethylene oxide condensates of straight and branched chain unsubstituted aliphatic alcohols having from 8 to 12 carbon atoms and having from 1 to 30 moles of ethylene oxide per mole of alcohol, and alkylphenol-ethylene oxide condensate having from 8 to 12 carbon atoms in the alkyl group and from 8 to 30 ethylene oxide units;

(f) from 0.005% to about 0.10% of salt ionizable in water selected from the group consisting of inorganic salts and salts of organic acids having from 1 to 4 carbon atoms;

(g) not more than about 1% of lower aliphatic alcohols; and

(h) aqueous vehicle consisting essentially of water sufiicient to make 100% 2. A composition according to claim 1 having at least about 1% of said supplementary low temperature stabilizer (d).

3. A composition according to claim 1 wherein said quaternary ammonium compound (a) is selected from the group consisting of distearyl dimethyl ammonium chloride ditallow dimethyl ammonium chloride dihexadecyl dimethyl ammonium bromide distearyl di(isopropyl) ammonium methosulfate said alkylamido imidazoline (b) is selected from the group consisting of the amidoethyl imidazolinium ethylsulfate obtained from hardened tallow fatty acid the amido ethyl irnidazolinium ethylsulfate obtained from hydrogenated oleic acid l-methyl-1-stearylamidoethyl-Z-heptadecylimidazolium methosulfate nsoso, Hz

and said fatty amido imidazoline (c) is selected from the group consisting of l-methyl-l-oleylamido ethyl-2-heptadecylimidazolinium methosulfate the amidoethyl imidazolinium ethosulfate obtained from unhardened tallow fatty acids. 4. A fabric softening composition having the following components in the approximate proportions as follows:

Percent Di stearyldimethyl ammonium chloride The alkyl amido-ethyl-imidazoline ethyl sulfate wherein the alkyl group is obtained from hardened tallow fatty acids 4 The fatty amido-ethyl-imidazoline methyl sulfate wherein the fatty group is obtained from natural tallow fatty acids 2 Dicocodimethyl ammonium chloride 2 The ethylene oxide condensate of C to C mixed primary alcohols having about 9 ethylene oxide units per mole of alcohol 0.5 Sodium citrate 0.05 Optical brighteners 0.25 Colorant 0.022

Water, balance to make 100% 10 there being in said composition from about 0.005% to about 0.10% of salts ionizable in water selected from the group consisting of inorganic salt and salts of organic acids having from 1 to 4 carbon atoms and not more than about 1% of lower unsubstituted aliphatic alcohols.

References Cited UNITED STATES PATENTS HERBERT B. GUYNN, Primary Examiner U.S. Cl. X.R. 

